After assembling windmill , which charged 12 -volt battery , the question arose , and what it can be powered . One of my main device was a laptop , it could be powered by a windmill in two ways :

Use converter 12V -> 220V , and it has to connect the standard charging , which will make of 220v 19v . This option does not suit me because the overall efficiency of such a system will be small , and precious energy is lost on converters . For example, the efficiency of the converter 12V -> 220V somewhere around 0.8 , and the charging efficiency of laptop around 0.9 , it turns out the total system efficiency of 0.72 , which is not very happy. Use